Doing remarkably little to combat the stereotype that women are emotionally frail and constitutionally incapable of dealing with stress, Professor Nancy Hopkins of MIT told the Boston Globe that she had to leave a lecture delivered by Harvard president Larry Summers because if she didn't she would have "either blacked out or thrown up."

What caused this damsel Hopkins to hie to her fainting couch? Why, the mere suggestion that there might be inherent differences between men and women when it comes to aptitude to the hard sciences.

Summers, who happens to be one of the world's most respected economists, was addressing an academic conference sponsored by National Bureau of Economic Research, and he raised the issue of innate aptitude while tackling the question of why the top ranks of the science profession are disproportionately male. But first he covered all of his bases, emphasizing how committed he is to expanding opportunities for women, combating discrimination and so forth.

The numerical predominance of men in science, Summers said, is chiefly explained by the commonsense, and commonly agreed upon, observation that the demands of motherhood tend to interfere with careers that require vast quantities of time at a very young age. Just like top lawyers and bankers, Summers explained, jobs requiring 80-hour workweeks disproportionately hurt women who tend to be primary caregivers for children for long stretches of time.

But then, in a spirit of academic open-mindedness, Summers raised the possibility that "innate difference" might be a factor as well. According to reports, he didn't necessarily embrace this view so much as throw it out for discussion. Indeed, before he raised this point he apparently said several times, "I'm going to provoke you" - which Dr. Hopkins might have noticed had she been able to hear over her ideological agenda.

"When he started talking about innate differences in aptitude between men and women, I just couldn't breathe because this kind of bias makes me physically ill," Dr. Hopkins told The New York Times. "Let's not forget that people used to say that women couldn't drive an automobile."

That's true. "People" also used to say that women aren't as tall as men, that men are more aggressive than women, that women are the ones who make babies, that men are physically stronger than women, and all sorts of other things that happen to be true. The mere fact that "people" used to say some things that weren't true doesn't mean that everything people used to say is untrue - even if some of those comments offend Hopkins' delicate sensibilities.

In fact, the scientific consensus is that there are innate cognitive differences between men and women - as groups. Individual men and women can be geniuses or morons (though the data suggest that men tend to produce more of both than women).

Men tend to perform better at spatial tasks - rotating three-dimensional objects in their mind, for example - as well as some mathematical and navigational tests. Women, on the other hand, are better at word games of various kinds, and they beat men at identifying matching items rapidly and putting the right-shaped pegs in the right holes. This is all fairly uncontroversial stuff - you can find a nice summary on the Web in a Scientific American article called "Sex Differences in the Brain" from May 13, 2002.

But don't show it to Dr. Hopkins. She may lose her lunch.

Now, I don't mean to be sexist when mocking Ms. Hopkins. I don't think her media-savvy hysteria has much to do with her sex. I think it has everything to do with a species of liberalism and/or feminism which is completely at odds with the best traditions of scholarship and liberalism, properly understood.

Ms. Hopkins made a name for herself a few years ago by whining incessantly about gender discrimination at MIT. Indeed, she complained so much that she was able to finagle the chairmanship (sorry, the chairpersonship) of a committee tasked with finding discrimination at MIT. Shockingly, Dr. Hopkins found discrimination! Her report made her a hero in the pages of The New York Times, which dubbed her a "reluctant feminist" in the headline of its gushing profile of her.

The report, which emphasized the feelings of anonymous female professors, found that discrimination manifested itself in a "stealth-like" way at MIT - which is generally PC code for "I'm not going to provide any evidence." The supposedly convincing evidence was kept secret, while the official report explained: "Discrimination consists of a pattern of powerful but unrecognized assumptions. . Once you 'get it,' it seems almost obvious."

Indeed.

This is perfectly consistent with Dr. Hopkins' current schtick - which got her a nice, sympathetic interview on the "Today" show and newspaper coverage around the world. In the past, women used to claim that vulgar language would cause them to grow ill or faint. Now feminists like Hopkins use the same tactic to silence ideologically unacceptable ideas and to intimidate the intellectually curious. That's the stereotype Dr. Hopkins is reinforcing: that feminists and the left are pro-science and pro-scholarship as long as they already agree with the conclusions.